Ion implantation is used to form p-doped and n-doped regions in semiconductor materials. Ionized impurity atoms are accelerated and directed at a surface of a single crystalline semiconductor substrate. The ionized atoms enter the crystal lattice, collide with the atoms of the lattice and come to rest at a depth determined by the acceleration voltage as well as the impurity and substrate materials. Ion implanting results in vertical dopant profiles showing in substance a Gaussian distribution, wherein the distance of the maximum concentration to the semiconductor surface is a function of the acceleration voltage and the standard deviation is a function of material parameters of the impurities and the substrate. It is desirable to provide more uniform dopant distributions in semiconductor devices.